IG window units are known in the art. For example, see U.S. Pat. Nos. 6,014,872; 5,800,933; 5,784,853; 5,557,462; 5,514,476; 5,308,662; 6,632,491; 5,306,547; and 5,156,894, all of which are hereby incorporated herein by reference. An IG window unit typically includes at least first and second substrates spaced apart from one another by at least one spacer and/or seal. The gap or space between the spaced apart substrates may or may not be filled with a gas (e.g., argon) and/or may or may not be evacuated to a pressure less than atmospheric pressure in different instances.
Many conventional IG window units include low-E coating (e.g., multi-layer coating including at least one IR reflecting layer such as a silver-based layer for reflecting at least some infrared radiation) on an interior surface of one of the two substrates. While such IG units enable significant amounts of infrared (IR) radiation to be blocked so that it does not reach the interior of the building (apartment, house, office building, or the like), such IG units are typically lacking in terms of blocking UV radiation. In other words, the low-E coatings provided on IG units while capable of blocking satisfactory amounts of IR radiation are often not capable of blocking as much UV radiation as would be desired.
In view of the above, it can be seen that there exists a need in the art for an IG window unit that is capable of blocking both (a) significant amounts of IR radiation, and (b) significant amounts of UV radiation, so that the blocked amounts of IR and UV radiation do not reach the interior of the building in which the IG window unit is mounted. In certain embodiments, there may also exist a need in the art for a method of making such an IG window unit.
Commonly owned U.S. Pat. No. 6,632,491 is incorporated herein by reference, and includes a low-E coating on one substrate and a UV blocking coating on the other substrate of an IG unit. However, it will be appreciated that in the '491 Patent the low-E and UV coatings are on opposite substrates, thereby requiring IG window fabricators to use two pieces of coated glass (which is more prone to damage) for each IG unit.
It will be appreciated that there exists a need in the art for an IG window unit that is capable of blocking both (a) significant amounts of IR radiation, and (b) significant amounts of UV radiation, so that the blocked amounts of IR and UV radiation do not reach the interior of the building in which the IG window unit is mounted, and is also designed so that IG window fabricators can manufacture such windows with less risk of damage. In certain embodiments, there may also exist a need in the art for a method of making such an IG window unit.